Yup. It's not an "issue" and there's nothing you can do about it. If Earthlink wants to work with RIM to improve delivery times then that would make a difference. Short of that what you get is what you get.

If you can live with the caveats (namely, you can't reply to Earthlink email with your Earthlink address) you can forward your Earthlink mail to your *.blackberry.net address for faster delivery.